Iron effect pigments

ABSTRACT

The present invention is concerned with soft-magnetic iron effect pigments with metallic luster, which are produced by grinding reductively treated carbonyl iron powder, and which are passivated either during grinding or subsequent to the grinding. The products find application in the decorative and functional fields in paint and lacquer coatings, coloring of plastics, in printing, cosmetics, and glass and ceramics.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is directed to an iron effect pigment.

[0003] 2. Background Art

[0004] Flakes of iron are produced according to the current standardtechnology from granular iron, which is obtained by atomizing molteniron. The pigment production takes place by means of crushing or millingprocesses whereby the granules are reduced to small pieces and deformed.As with all metal pigment production methods, lubricants are added inthe process to prevent cold welding of the pigment particles. Thestandard technology for producing flake shaped iron pigment is describedin detail in examples 1 and 8 in EP 0673 980. The shortcomings of thatproduction process lie in the fact that granular iron that is producedby atomizing is always relatively coarse and has a wide particle sizedistribution. As a result, only relatively large flakes can be producedfrom granular iron produced by atomizing. Flakes in the preferred rangefor effect pigments of 6 to 36 μm can be obtained only through energyextensive and lengthy grinding processes, or one has to limit oneself tousing sieve fractions before and/or after the grinding. This makes theirproduction unprofitable. The shape of the iron flakes that are obtainedby atomizing is irregular, with rough surfaces and frayed edges, whichresults in a relatively low optical quality due to a greater number oflight-scattering centers.

[0005] Metal flakes of high optical quality can be obtained by grindingonly if the grinding process is performed so gently that the granulesare merely deformed and not reduced in size. The prerequisite for such agentle grinding is a high ductility of the metal granules, which ispresent in aluminum, for example. As is well known, aluminum flakes of aparticularly high optical quality can be produced by using granules ofspherical morphology. If these granules are merely deformed and notreduced in size during the grinding, flakes are obtained that have roundedges and a smooth surface (so-called “silver dollars”). Because oftheir regular shape, due to the lesser light scattering when applied ina coating, these pigments have a significantly more directed reflectionof incoming light than pigments of a comparable size distribution that,however, were obtained from shapeless granules and/or by reduction insize.

[0006] Optically even superior metal pigments can be produced byphysical vapor deposition (PVD) processes. In this alternate technology,metal films are deposited onto substrates in the vacuum and subsequentlyremoved and pulverized. Those pigments, however, are disproportionatelyexpensive and, with the exception of aluminum, have so far found noapplication. Iron flakes that could possibly be produced according tothat method have been left out of account within the framework of thisinvention.

[0007] Flakes from iron alloys, such as alloyed special steel—orHastalloy—flakes are also not an object of the present invention. Theygenerally lack the specific shade and luster of iron. Furthermore, ironalloys usually display a less favorable ductility and a lesser or noutilizable magnetism.

SUMMARY OF THE INVENTION

[0008] The present invention focuses on unalloyed iron. The goal of theinvention was to develop a high-luster, soft-magnetic effect pigmentwith the typical coloring of iron that is available in a passivatedform. The manufacturing process shall be guided in such a way that thedeformation and not the reduction in size plays the main role in thegrinding phase. The effect pigment should find use in the decorative butalso in the functional field, in coatings, plastics, printing,cosmetics, and in glass and ceramics.

[0009] Surprisingly, it has now been found that when carbonyl ironpowder is used as the starting material, iron flakes can be produced bygrinding in a size that is particularly desirable for automobile paints,and in a “silver dollar” shape that is known from aluminum. Furthermore,with an appropriately gentle grinding process, the size-to-thicknessratio can be adjusted in a surprisingly controlled manner. Carbonyl ironpowder that has been treated in a reducing manner is characterized by aparticularly high degree of purity, ductility, small particle size,spherical morphology and narrow particle size distribution. The effectpigments of soft iron display ferromagnetic behaviors and, when used inan application, can be oriented in the magnetic field, which producesvery impressive patterns that appear three-dimensional to the human eye.

[0010] The product and process development for the present invention areaimed at eliminating the iron atomizing process as well as the reductionin size of the granular iron obtained by atomizing. It is, in fact,impossible, even with the most modern nozzle technology, to producestarting granules for the grinding process that come even close toattaining the positive properties comparable to carbonyl iron powderthat are necessary for the production of iron effect pigments in a“silver dollar shape”. If one wants to avoid the size reduction processin the milling of granular iron, an average particle size of 1 to 15 andpreferably 2 to 8μ in the base product will be required for a finalproduct with an average flake diameter of 6 to 36μ. The base productshould have a narrow particle size distribution, which is the case withcarbonyl iron powder.

[0011] Carbonyl iron powder is produced by decomposition of vapor-stateiron pentacarbonyl Fe(CO)₅ in cavity decomposers (see leaflet by BASFAG, Ludwigshafen, RCA 3210, 0686-2.0, FIG. 1) and is availablecommercially (BASF AG, Ludwigshafen, as well as ISP, Wayne, N.J.).However, these powders initially have a relatively high grain hardnessand contain up to 1.5% carbon, approximately 1% oxygen and up to 1%nitrogen. Their iron content is around 97%. If these powders aresubjected to a treatment at an increased temperature in a hydrogen flowor in a hydrogen-containing atmosphere, the so-called “reduced carbonyliron powder” is obtained, which is characterized by an iron content ofover 99.5% and a high ductility, and which is particularly suitable as astarting product for grinding for the production of iron effectpigments. Reduced carbonyl iron powder is also available commercially(BASF AG, ISP). The powders are currently used in the field of powdermetallurgy, for medical purposes, and in the production of electroniccomponents.

[0012] The use of reduced “carbonyl iron power” with an average particlesize of 0.5 to 15 μm, preferably 1 to 10 μm, and the narrow grain sizedistribution that is typical for carbonyl iron powder, permits theproduction of iron flakes with a high degree of luster and aspecifically adjustable diameter-to-thickness ratio (shape factor), anda shape resembling the “silver dollar” shape of aluminum pigments.

[0013] The nano/microhardness of reduced granular carbonyl iron wasmeasured in comparison with granular aluminum (purity 99.7%). Thedetermination was performed using a Hysitron TriboScope™ based onsections embedded in epoxy resin. Carbonyl iron powder showed a threetimes lesser nano/microhardness (0.61 GPa) than the granular aluminum(1.85 GPa).

[0014] The lower microhardness of carbonyl iron permits a relativelygreater deformation of the granules as compared to the aluminum. Thiseffect is of importance among other things for the covering power ofmetallic coatings. Aluminum pigments have a high specific coveringpower, not least due to their low density (2.7 g/cm³). Metals withhigher densities, such as brass, iron (7.87 g/cm³), etc., arecomparatively at a disadvantage. However, this disadvantage can becompensated for by a greater shape factor during the grinding ofcarbonyl iron powder.

[0015] The shaping of the particles in the course of the grindingprocess may take place dry or wet, i.e., in the presence of solventssuch as white spirit, mineral oil, toluene, alcohols, chlorinatedhydrocarbons, water, or mixtures of the same. The grinding medium may besteel balls with a size of 0.5 mm to 25 mm. Other grindings bodies,e.g., of ceramics or glass, may also be used. Wet grinding is preferredsince it is gentler and permits an easy size classification of theground product with decanters after the grinding step. Wet grindingfurthermore permits the easy distribution of lubricants or inhibitorsubstances or anticorrosive agents throughout the entire ground product.

[0016] The mills can be agitating ball-type mills, edge mills, drum ballmills and other aggregates. Particularly preferred are revolving tubularball mills. Specifically, the process for producing high-luster,soft-magnetic effect pigment is such that “reduced carbonyl iron powder”of a certain particle size is entered into a ball mill together with asolvent, such as for example, white spirit. To prevent cold welding,lubricants, such as oleic acid, stearic acid or also special inhibitorsubstances are added, the amount of which depends on the free specificsurface area (BET) of the rolled iron pigments. Generally, 0.5 to 6%oleic acid or stearic acid are used relative to the weight of the ironpowder. The grinding time is between 0.3 and 10 hours.

[0017] The passivation of the iron flakes may take place throughaddition of inhibitor substances and anticorrosive agents, eitheralready during the grinding phase or through a corresponding coatingsubsequent to the grinding phase. After completion of the grinding andoptional subsequent coating, the product is filtered, dried andsubjected to a protective sifting. The flake shaped iron particles mayoptionally also be subjected to a size classification in the decanterprior to filtering and separated in the process according to differentparticle size fractions.

[0018] For dry grinding, “reduced carbonyl iron powder” is entered intoa ventilated ball mill together with the lubricant, and optionally alsowith inhibitor substances, and ground. As with the wet grinding, theballs are composed of steel, ceramics or glass. The smaller the enteredcarbonyl iron powder, the smaller the balls may be. In practice, ballsbetween 0.5 and 8 mm are normally used.

[0019] For an efficient deformation of the spherical particles of thecarbonyl iron powder, the same must have the highest possible degree ofpurity. The reduction, i.e., the annealing of the carbonyl iron powderin a hydrogen-containing atmosphere must, therefore, result in powdersthat are depleted as much as possible regarding their carbon andnitrogen content.

[0020] The material properties of the reduced carbonyl iron powder mustcome as close as possible to those of soft iron, i.e., pure iron. Forthe efficient mechanical deformation in the ball mill, in particular, itis important that the particles have a hardness of less than 5.0 (Mohs'scale)—soft iron has a hardness of 4.5. The particles must be tough,ductile and polishable. The commercial “reduced iron carbonyl powders”generally meet this requirement profile. They have an iron contentgreater than 99.5%, carbon values ≦0.005% and nitrogen values ≦0.01%. Intheir oxygen content they are below 0.4%, most of the time even below0.2%. Metallic contaminants are present in the powders only in smallestquantities, such as nickel (0.001%), chromium (<0.015%) and molybdenum(<0.002%). The average particle sizes of the commercially availableproducts extend from 1 μm to 10 μm (see technical leaflets regardingcarbonyl iron powder by BASF and ISP). In the course of the reductiveannealing of carbonyl iron powder, agglomerates are occasionally formed.However, these can easily be removed by customary methods (sifting,decantation).

[0021] By using commercially available reduced iron carbonyl powder, itis possible, depending on the selected average particle diameter of thecharge, to produce flake shaped iron effect pigments with the averageparticle size of 3 to 60 μm, especially 6 to 36 μm. Thediameter-to-thickness ratio of the flakes can be adjusted by varying thegrinding time. A longer grinding time with otherwise identicalconditions results in a higher diameter-to-thickness ratio. While it ispossible, in principle, to set any diameter-to-thickness ratio between 5and 500, diameter-to-thickness ratios between 40 and 400 are generallypreferred.

[0022] The passivation of the flake shaped iron pigments is ofparticular importance since iron powder that has not been passivatedcan, in a finely distributed form, react violently with the oxygen inthe air, even producing flames. In the presence of water there will becorrosion. Two general passivation approaches play a role, which can beused individually but also jointly: passivation through inhibitors andpassivation through barrier layers of a chemical and physical nature. Ifinhibitors, because of their consistency, are also used as lubricants toprevent cold welding of the particles, they are preferably added alreadyduring the grinding process. Otherwise they are applied adsorbently ontothe pigment after the grinding.

[0023] Barrier layers are applied chemically onto the pigment. Thisgenerally does not entail any change in the optical appearance of thepigment as the barrier layers are relatively thin (10 to 100 nm) andadvantageously consist of a material with a low refraction index (<1.7)in order not to trigger any interference reflection.

[0024] The working mechanism of the passivation layers is complex. Inthe case of inhibitors it is usually based on steric effects. Themajority of inhibitors thus has an orienting effect in the sense of“leafing” and “non-leafing” (floating up and not floating up in themedium).

[0025] The inhibitors are usually added in low concentrations in theorder of magnitude of 0.1 to 6% relative to the weight of the carbonyliron powder. The following may be used for the passivation of ironflakes:

[0026] Organically modified phosphonic acids of the general formulaR—P(O)(OR₁)(OR₂) wherein R=alkyl (branched or unbranched), aryl,alkyl-aryl, aryl-alkyl, and R₁, R₂═H, C_(n)H_(2n+1), with n=1-6. R₁ maybe identical to or different from R₂.

[0027] Organically modified phosphoric acid and esters of the generalformula R—O—P(OR₁)(OR₂) with R=alkyl (branched or unbranched), aryl,alkyl-aryl, aryl-alkyl and R₁, R₂═H, C_(n)H_(2n+1), with n=1-6.

[0028] Pure phosphonic acids or esters may be used, or phosphoric acidsor esters, or mixtures of various phosphonic acids and/or esters, ormixtures of various phosphoric acids and/or esters, or any mixture ofvarious phosphonic acids and/or esters with various phosphoric acidsand/or esters.

[0029] Also mentioned should be the substance class of the oxygen,sulfur and nitrogen containing heterocycles, which include inhibitorssuch as mercapto-benzthiazolyl-succinic acid, furthermoresulfur/nitrogen-containing heterocycles such as thiourea derivatives,furthermore aliphatic and cyclic amines, including zinc salts ofaminocarboxylates, or polymeric amine salts with fatty acids.Additionally, higher ketones, aldehydes and alcohols (fatty alcohols),thiols, b-diketones and b-keto esters may be used as well, furthermoreorganically modified silanes and a multitude of longer-chained,unsaturated compounds. Also mentioned should be fatty acids,longer-chained mono and dicarboxylic acids and their derivatives. Theseinclude, among others, oleic acid and stearic acid. Inhibitors usuallyshow a very low solubility in the solvent during the wet grinding.

[0030] The passivation by means of anticorrosive protection barrierswith chemical and physical protection mechanisms can be implemented inmany ways. The barrier effect of the anticorrosive coating may beimproved, for example, through the action of phosphoric acid,phosphorous acid, molybdate-containing, phosphor-containing andsilicon-containing heteropolyacids, chromic acid, boric acid and otherknown anticorrosive agents as they are described, for example, in Farbeund Lack (1982), pages 183-188. Oxide layers, such as SiO₂, ZrO₂, Cr₂O₃or Al₂O₃ or mixtures of the same may also be formed. Preferred are SiO₂layers with layer thicknesses of 20 to 150 nm that are preparedaccording to sol-gel methods.

[0031] Flake shaped iron effect pigment has a use not only in thedecorative field (coatings, plastic coloring, printing, cosmetics) wherethe average special optics of iron flakes are of importance.

[0032] Based on the electric conductivity and high magnetic permeabilityof iron flakes, there are numerous specific applications over and abovethat in the functional field, such as in security printing. Iron flakescan furthermore be used as a product in the production of complex,multi-layer effect pigments, such as for example, interferencereflection pigments or optically variable pigments.

[0033] The invention will be described in more detail below withreference to the following examples, but without restricting it:

EXAMPLE 1

[0034] 100 g reduced carbonyl iron powder by firm BASF AG Ludwigshafenwith the designation “Carbonyleisenpulver CN”, average particle size 5.5μm.

[0035] (d10 value 3.5 μm, d90 value 15 μm), iron content 99.8%(C≦0.006%, NL<0.01%, O=0.18%) are entered into a ball mill of dimensions30 cm×25 cm, which is half-filled with 1.5 mm diameter steel balls.Added to this are 0.56 liters white spirit and 2.8 g of a mixture ofstearic acid and oleic acid. The mill is then closed and rotated for sixhours at 56 revolutions per minute. The mill is subsequently emptied,the grinding product is washed with white spirit and separated from thegrinding means by sifting (25 μm).

[0036] The obtained effect pigment displays a high degree of metallicluster and the magnetic permeability of soft iron powder. The followingparameters were determined from laser beam refraction measurements(Cilas measurements) for the size distribution: d₉₀:27 μm, d₅₀:18 μm(average particle size) and d₁₀:10 μm, and the specific surface wasdetermined based on BET measurements as 4 m²/g. In the appended FIG. 1,scanning electron microscope images of the pigments are shown, whichreveal a relatively round edge shape of the pigments. The parameters ofthe size distribution, as well as the shape are typical for “silverdollar pigments”.

[0037] From the appended FIG. 2 it is apparent that the pigments arerolled very thin. The thickness of individual iron flakes isapproximately 100 nm, which is less than half of corresponding aluminumpigments.

[0038] The average thickness of the pigments was determined by means ofa so-called spreading method: 0.2 g of the pigment powder are enteredinto a 5% solution of stearic acid in white spirit for 15 minutes. Thestearic acid attaches to the pigment surface and imparts to the same astrongly hydrophobic character. Afterwards a small, defined quantity ofthe powder is sprinkled onto purified water in a “spreading pan”. Aftercareful stirring of the pigment film to better distribute the pigments,the same is spread by means of two metal wands on the water until acovering, shiny film develops. If this film is expanded too far, holesappear. If it is compressed too much, it takes on a wrinkled pattern. Inthis manner it is possible for a person with experience in the art toreproducibly create a “mono-layer” metal pigment film on the water. Thesurface of the spread film is measured. The specific surface iscalculated from:$A_{spec} = {2*\frac{{spread}\quad {{surface}\quad\left\lbrack {cm}^{2} \right\rbrack}}{{originally}\quad {weighed}\text{-}{in}\quad {{quantity}\quad\lbrack g\rbrack}}}$

[0039] From this, the average thickness of the flakes can be calculatedin nm: $\overset{\_}{d} = \frac{10^{7}}{A_{spec}*\delta_{Fc}}$

[0040] A value of 146 nm was determined for the above-described sample.

[0041] If one disperses the flake shaped iron powder 30% in a cellulosenitrate lacquer solution and applies it with a spiral doctor knife, oneobtains a coating with very high covering power, a metallicplatinum-like luster and excellent flop behavior.

[0042] In the appended FIG. 3, the doctor blade impression ischaracterized colorimetrically and compared to a comparable aluminumpigment (Stapa MEX 2156, d₉₀:25 μm, d₅₀:16 μm and d₁₀:9 μm; silverdollar pigment). The brightness L* has been applied against the viewingangle relative to the reflection angle (angle of incidence of 45°). Whatbecomes apparent is the very much darker behavior of the iron pigmentacross all viewing angles.

[0043] The metallic “flop” is the significant decrease of the brightnessL* near the glancing angle from higher angles. A measure for the flopdeveloped by firm DuPont from brightness values is represented by thefollowing equation:${{Flop}\quad {index}} = {2.69 \times \frac{\left( {L_{15^{\circ}}^{*} - L_{110^{\circ}}^{*}} \right)^{1,11}}{\left( L_{45^{\circ}}^{*} \right)^{0.86}}}$

[0044] Flop values result for the compared examples of 17.5 for aluminumpigments an 18.9 for the iron pigments. The iron pigment thus has ahigher flop.

[0045] Dispersed into molten PVC, the iron particles can be oriented byapplying an external magnetic field as long as the PVC is in its moltenstate. Decorative light/dark patterns that appear quasithree-dimensional are obtained as a result of the orientation.

EXAMPLE 2

[0046] 100 g reduced carbonyl iron powder as in Example 1 are enteredinto a ball mill of dimensions 30 cm×25 cm, which is half-filled with1.5 mm diameter steel balls. Added to this are 0.56 kg white spirit and6 g stearic acid. The mill is then closed and rotated for six hours at90 revolutions per minute. The mill is then emptied, the ground productis washed with white spirit and separated from the grinding means.

[0047] The iron pigment is printed as a dispersion in a gravure presswith a cylinder, with a gravure screen with 70 dots/cm. High-glossprinting patterns are obtained, with a platinum-like metallic hue thathas so far been unknown in the printing industry.

EXAMPLE 3

[0048] 100 g reduced carbonyl iron powder as in Example 1 are enteredinto a ball mill of dimensions 30 cm×25 cm, which is half-filled with1.5 mm diameter steel balls. Added to this are 0.56 g white spirit and 6g octanophosphonic acid ((HO)₂OP—(C₈H₁₇)).

[0049] The mill is then closed and rotated for six hours at 90revolutions per minute. The mill is then emptied, the ground product iswashed with white spirit and separated from the grinding medium. Theobtained pigment displays a specific luster and high magneticpermeability. The average particle size of the powders is measured as 14μm by laser beam refraction (Cilas measurements). Examinations with thescanning electron microscope reveal a diameter-to-thickness ratio of theflakes of approximately 70:1.

[0050] If the pigment is dispersed into a cellulose nitrate lacquersolution with a weight ratio of 20% and wiped with a doctor blade, thecoating displays a high covering power and a titanium-like metallicluster.

EXAMPLE 4

[0051] 100 g reduced carbonyl iron powder by firm BASF AG Ludwigshafenwith the designation “Carbonyleisenpulver CN” with an average particlesize of 5.5 μm (d10 value 3.5 μm, d90 value 15 μm), iron content 99.8%(C≦0.006%, NL<0.01%, O=0.18%) are entered into a ball mill of dimensions30 cm×25 cm, which is half-filled with 1.5 mm diameter steel balls.Added to this are 0.56 liters white spirit and 1 g oleic acid.

[0052] The mill is then closed and rotated for six hours at 58revolutions per minute. Afterwards the mill is emptied, the grindingproduct is washed with white spirit and separated from the grindingmedium.

[0053] The obtained effect pigment displays a high metallic luster andthe magnetic permeability of soft iron powder. The average particle sizeof the flake shaped iron oxide is 15 μm, as determined by laser beamrefraction (Cilas measurements). Scanning electron microscope imageswere used to determine a diameter-to-thickness ratio of the flakes ofapproximately 50:1.

EXAMPLE 5

[0054] 100 g reduced carbonyl iron powder by firm ISP, Wayne, N.J. withthe designation R-1510, iron content 99.7%, average particle size 8.2μm, is ground under conditions as in Example 4.

[0055] The obtained product with metallic luster and high magneticpermeability is magnetically separated from the grinding medium,filtered and subsequently stirred for over one hour in 1 liter 0.1%aqueous H₃PO₄ solution. The flake shaped iron pigment is subsequentlyfiltered and dried in the drying chamber at 95° C. The product is notsusceptible to rust for a period of 60 days.

EXAMPLE 6

[0056] 350 g of the passivated iron effect pigment produced in Example 4is entered into a heatable technical college mixer with a capacity of 10liters and kept in motion with mixing means at 100° C. With the aid of acarrier gas flow (300 l/h, N2 as carrier gas), 3-aminopropyltrimethoxisilane (AMMO) and water are passed into the mixer using anevaporator. After 30 minutes the effect pigment is removed from themixer.

[0057] The effect pigment, which is coated with silane on all sides,displays a good corrosion resistance in water lacquers and does notreveal any corrosion effects over a period of 60 days.

EXAMPLE 7

[0058]90 g iron pigments, as produced in Example 2, are dispersed in 300ml isopropanol in a 1-liter laboratory reactor and brought to the boil.One adds 20 g tetraethoxysilane and 5 minutes later 11.6 g distilledwater. Afterwards 9.6 g 25% aqueous NH₄OH solution are passed in overthe course of 2 hours and the mixture is allowed to boil for another 4hours. The reaction mixture is then cooled down, stirred overnight,filtered off by suction the next morning and dried in the vacuum dryingchamber at 90° C. The product has a SiO₂ content of 5.8%, whichcorresponds to a SiO₂ conversion yield of 96%. In standard run tests,the product shows an excellent run resistance and is thus suitable foraqueous lacquer systems.

What is claimed is:
 1. A flake shaped iron pigment, wherein the pigmentis produced from reductively treated carbonyl iron powder.
 2. A flakeshaped iron pigment according to claim 1, produced from reductivelytreated carbonyl iron powder of at least 99.0% purity.
 3. A flake shapediron pigment according to claim 1, wherein it has a particle size of thecarbonyl iron powder of 0.5 to 100 μm, especially 1 to 60 μm.
 4. A flakeshaped iron pigment according to claim 1, wherein it has an averageparticle size of the iron flakes of 5 to 100 μm, especially 6 to 60 μm,and average thicknesses of 500 to 30 nm, especially of 200 to 40 nm. 5.A flake shaped iron pigment according to claim 1, wherein the ironpigment is coated with a passivating inhibitor and/or anticorrosiveprotection coating.
 6. A flake shaped iron pigment according to claim 5,wherein the passivating anticorrosive protection layer is composed ofsilicon oxide, zirconium oxide, aluminum oxide/hydroxide, phosphate,phosphite, chromium oxide, borate or mixtures of the same.
 7. A flakeshaped iron pigment according to claim 5, wherein the inhibitor coatingis composed of fatty acids, carboxylic acid derivatives, organicphosphates and phosphonates and their esters, organically functionalizedsilanes, aliphatic or cyclic amines, aliphatic and aromatic nitrocompounds, oxygen-containing, sulfur-containing or nitrogen-containingheterocycles, sulfur/nitrogen compounds of higher ketones, aldehydes andalcohols, thiols, b-diketones, b-ketoesters or mixtures of the same. 8.A flake shaped iron pigment according to claim 1, wherein a passivatinganticorrosive coating according to claim 6 is applied initially,followed by an inhibitor coating according to claim 7, or an inhibitorcoating according to claim 7 is applied first and then a passivatinganticorrosive coating according to claim
 6. 9. A method for theproduction of pigments according of to claim 1, wherein the dry or wetgrinding of reductively treated carbonyl iron powder in the presence ofauxiliary grinding agents.
 10. A method for the production of pigmentsaccording to claim1, wherein dry or wet grinding of reductively treatedcarbonyl iron powders in the presence of auxiliary grinding agentsand/or inhibitors and/or anticorrosive compounds.
 11. A method for theproduction of pigments according to claim1, wherein the wet or drygrinding of reductively treated carbonyl iron powder and subsequentapplication of an anticorrosive barrier.
 12. Use of flake shaped ironpigment according claim 1 as effect pigment in the painting and lacquerindustry for coloring plastics, in printing, cosmetics and as reflectormaterial in the production of multi-layer effect pigments.
 13. Use offlake shaped iron pigment according claim 1 as magnetic effect pigmentin the painting and lacquer industry, for coloring plastics, inprinting, cosmetics, and as reflector material in the production ofmulti-layer effect pigments.
 14. Use of flake shaped iron pigmentaccording claim 1 as magnetizable effect pigment in security printing.